1. Field of the Invention
The present invention relates to a retention apparatus for computer systems, and more particularly to a retention apparatus for expansion cards of a computer.
2. Description of the Related Art
Microprocessor based computer systems typically require or include facilities for connecting one or more expansion cards to the system. Expansion cards extend the capabilities of computer systems by providing dedicated hardware to achieve a variety of tasks. Graphics adapters, high speed network controllers, hard disk controllers, sound cards, and modem cards are among some of the more common types of expansion cards, although those knowledgeable in the field of computer systems will recognize a wide variety of other types of expansion cards.
Typically, expansion cards are interfaced to the microprocessor (or microprocessors in a multi-processor system) by physically inserting the expansion card into an expansion card connector of a motherboard. In many cases, the expansion card comprises facilities for making an external connection to the expansion card. A network adapter card, as an example, typically comprises a socket for connecting an external cable to the adapter card. The expansion card must be maintained in a precise position such that the socket is accessible. Moreover, because external connections to expansion cards are achieved by incorporating expansion slots in a chassis of a computer system, it is important to maintain the positioning of expansion cards within their respective expansion card connectors during system operation to insure reliable operation. Those familiar with expansion cards and expansion card connectors will appreciate the ease with which a slight displacement or movement of the expansion card can result in a faulty connection. Thus, maintaining precise positioning of expansion cards is an important issue in the design and manufacturing of computer systems. Historically, the secure positioning of expansion cards was maintained by screwing each expansion card into place with one or more securing screws. Unfortunately, the use of separate screws to secure each expansion card undesirably increases the amount of time and effort required to install, remove, replace, and otherwise service the expansion cards in a system.
A significant amount of effort has been devoted to simplifying the means by which the positioning of expansion cards is maintained. See for example U.S. Pat. No. 6,215,668, which teaches a complex retaining unit for securing an expansion card via the application of a wedging force; and Taiwan Pat. No. 472906, which discloses a slidable block and a support base mechanism for engaging expansion cards. Unfortunately, these inventions typically require highly intricate retention structures and a rotating or sliding mechanism, which introduces undesirably expensive extra hardware to the system component list.